PURPOSE: To obtain a superconducting magnet whose superconducting characteristic is not deteriorated by a heating operation or a cooling operation by a method wherein a material whose coefficient of linear expansion within a temperature range of 4.2 to 1273 K is within a specific range is used for a bobbin on which a superconducting wire composed of a Chevrel-phase compound is wound.
CONSTITUTION: At a superconducting magnet formed by winding a superconducting wire 2 composed of a Chevreal-phase compound on a bobbin 5, a material whose coefficient of linear expansion is at 10×10-6 or higher and 14×10-6 or within a temperature range of 4.2 to 1273 K is used for the bobbin 5. For example, a wire material by a composite body, for PbMo6S8-based compound superconducting wire use, which has been stretched up to a diameter of 1.00mm is knitted to form a bag by using a quartz fiber and is insulation-treated. Then, a bobbin 5 by a mica-based machinable ceramic whose coefficient of linear expansion is at about 12.3×10-6 is manufactured; the wire material 2 which has been insulation-treated is wound on the bobbin 5 in a solenoid shape. Then, the wire material 2 which has not yet been heat-treated of a solenoid coil is heat-treated at 1000°C for two hours in an argon atmosphere; a PbMo6S8-based compound is produced; after that, the coil is vacuum-impregnated with an epoxy material; the wire material is fixed.
FUJIWARA FUMIO
NAGAI TAKAYUKI
